Starting and operating circuit for fluorescent lamp



Sept. 6, 1955 w. s. H. HAMILTON 2,717,333

STARTING AND OPERATING CIRCUIT FOR FLUORESCENT LAMP Filed Feb. 15. 1950 T 5 Sheets-Sheet l xlj INVENTOIZ'. William 5 H- Hamilum,

ATTORNEY STARTING AND OPERATING CIRCUIT FOR FLUORESCENT LAMP Filed Feb. 15, 1950 3 Sheets-Sheet 2 W. S. H. HAMILTON Sept. 6, 1955 9a 8a. 9a

INVENTOR: William 5 H-Hami1tnn,

a a. ATTORNEY.

p 6, 1955 w. s. H. HAMILTON 2,717,333

STARTING AND OPERATING CIRCUIT FOR FLUORESCENT LAMP Filed Feb. 15, 1950 5 Sheets-Sheet 3 H E E i i 1/7 fl+ I k z 5 L H P I I 1 O I IO a a. o 0 ,/3 b BL +/34 0 p r f z r 5 C C Hailp n I 20 i l7 I 1 L /5 /7 I9 I I INVENTOR', 4 7 William 5- H-HELTH11[UT1 19 5- -F a f I D I ATTORNEY.

United States Patent STARTING OPERATING CIRCUIT FOR FLUORESCENT LAMP William s. H. Hamilton, Larch mont, N. Y. Application February 15, 1950, Serial No. 144,345 3 Claims. (Cl. 315-103) This invention relatesto improvements in starting and operating circuits for fluorescent lamps, particularly those operated on 60-volt and 110-volt DC. and A. C. sources of current supply, such as lamps of the 12", T-8 (1 dia.), T-12 (1% dia.), 18",. T-12 (1% dia.) and 24", T-12 (1% dia.) types, but which are adapted for use in connection with other hot-cathode lamps having like operating characteristics.

One object of the invention is to provide novel and improved circuit organizations employing a thermoelectro-magnetic starter, preferably but not necessarily of plug-in type, for supplyingpreheating and operating current to the lamp in such a manner as to secure quick starting and re-starting actions.

Another object of the invention istoprovide a starter embodying a thermal switch and a relay operating in conjunction therewith to preheat the lamp and to stop the preheating action and start the lamp into operation as soon as it is sulficiently heatedto fire.

Still another object of theinvention is to provide a starter of the described type;which will permit of a practically instantaneous restarting of a lamp which has been turned ofi and then turned on again shortly, regardless of the position of the thermal switch. I

Still another object of the invention is to provide a starter of the type described in which a thermal switch and a relay are so compactly. constructed, combined and arranged for use as to adapt the same ,to be enclosed in a plug-in can" or casing of the same or practically the same size as that of a conventional starter, such as the FS44 starter,v and used in the same or a similar socket with little or no circuit wiring changes.

Still another object of the invention is to provide a starter of this type which issimple of construction, reliable and efficient in operation, and adapted as exemplificatively disclosed or 'in suitably modified forms to be used in connection with different types of lamps operating on either D. C. or A. C. sources of current supply.

With these and other objects in view, which will appear in the course of the. subjoined description, the invention consists of. the novel features of construction, combination and arrangements of parts hereinafter more fully set forth, and as shown in the accompanying drawings, in which;

Figure 1 is aschematic diagram of one form of circuit as adapted for operation with a D. C. fluorescent lamp and employing. a thermo-electro-rnagneticstarter embodying my invention, showing the parts in normal starting position. V V I, I l

Fig. '2 shows an enlarged detail view of the circuit disclosedv in Fig. 1, showing" thestarter switches as normally arranged in closed position for a starting action.

Fig. 3 is'a similar view showing the relay switch opened to break th'e preheating circuit and showing in full and dotted lines closed and opened positions of the thermostatic switfch. This figure shows in full lines the arrangement of the parts afterfihe lamp has been operating for a fews'econds. i

Fig. 4 is a modified form of the circuit shown in Fig. :1 A and using the sametype of starter. I I a i Fig. 5 is a diagram of a still'further modified form of circuit employing a modified formof starter,v the parts appearing in normal position ready to start the lamp.

Fig. 6 is an enlarged detail view of a portion ofnthe; circuit shown in Fig. 5 showing-the starter in the position. taken after the lamp has been operating for a few seconds. Fig. 7 is a diagram of a still further modified form ofv circuit employing a starter ofthe type shown in Figs. 5;

position ready to and. 6, the parts appearing in normal start the lamp.

Fig. 8 is an enlarged detail 'view. of a; portion of the circuit shown in Fig. .7 with the starterin'the position f,

taken after the lamp has been operating for a few seconds.

Fig. 9 is aview in front elevation ofmy invention as? embodied in a starter adapted .for use in connection with a lamp socket, showing the starter casing body in vertical section.

Fig. 10 is a similar view in rear elevation of the starter. Fig. 11 is a section through the starter on an enlarged scale taken on line 1111 of Fig. 9. 1

Figs. 12 and 13 are horizontal transverse sections taken on lines 12-12 and 1313of Fig. 9.

Fig. 14 is a view of the'thermostatic switch supporting disk and the switch heater carried thereby.

Referring now particularly to Fig- 1' of the drawings;-

1 represents the gas containing envelope of the lamp having the negative cathode and positivefilamentary elec-c trodes 2 and 3, respectively,at least one of which is adapted to be preheated to start the lamp. In the case of a circuit such as shown inzFig. 1, which is designed to:

operate primarily on D. C., it is only necessary to heat the negative cathode filament, sothat the positive filament 1 may be short circuited. Connected with:these electrodesx are operating conductors or leads .4 and 5 forming with the electrodes an operating circuit, which conductors are adapted to be connected at points 6 and 71to theiterminals of a line, or supply, circuitadapted to be opened and closed in practice by suitable means. In the input] and output portions of conductor 4 are arranged an induc-- tive reactance 8 and a ballast lamp 9, which maybe of any suitable type,-and included also in this conductor is the coil, or winding, 10 of the relay of "the combinedl thermal and relay switch device, hereinafter described.

Extending from the conductor 4 at a point between the' reactance 8 and the lamp is a preheating conductor com prising input and output branches, or sections, 11 and 12 and an intermediate switch circuit branch 13. A relay, or electro-magnetic, switch 14 normally connects, through its contacts 15, 15 and the output end of'branch- 11 with the input end of branch-13 and a'thermostatic, or'

thermally operated, switch 16 normally connects through its contacts 17, 17' the output end of branch 13 with the input end of branch 12. -In the branch 12' is a current .limitingresistance 18 and in the branch '13 is a heating resistance 19 for heating the switch 16. An a'rc suppressing condenser 20 extends across the adjacent ends of branches 11 and 12 to suppress or reduce the arcing'at the contactsof the thermal switch or relay when breaking 1 the circuit through the reactance 8.

The conductors 11, 12, 13, and switches 14 and 16 form the component parts of apreheating circuit of the starter which governs the flow of preheating current to the lamp. Normally the switches are closed as shown to coactively establish a preheating circuit to preheat the filament when the line-circuit is closed for-a starting ac-' .Pa tented Sept. 6, 1955 switch-elements .and their coacting members are preferably arrangedas an assemblyso alinedthat they may be disposed in close compass and so as to be enclosed within a can or plug-in container casing having plug-in prongs or-contacts-to fit within a receiving socket for connection with the associated conductors.

The-arrangement of the parts'comprising the starter may, in fact, be such as-to-adapt them to fit within a can of theasame sizeas thercan of the well known -F$44 starters By-this meansa combined thermal switch and relay starter-embodyingmy. invention may be used in connection Withinstalled lamps of the types described and other similar types with-littleor no rewiring. A furthenadvantage of this structure is that, if mounted in an FS+44 starter socket, it will :be reversible as to position, as said socket is so arranged by the size of its openings toreceive the-prongs of the starter in only two positions,eitherof which gives proper operation of the circuit. The relay may be-. .ofany suitable type and for simplicity-may be ofthe type shown in Figs. 2 and 3 in which theswitch14 is spring closed automatically and adapted to be.opened-- when attracted by energization of coil 10, while thermostatic switch 16 may be one of quickacting-snap type-comprising a switch member 16 connected-by an insulated stern'toa concave-convex thermostatic disk 16' normally bowed in one direction to hold switch 16 closed and adapted to'be'bowed in the opposite direction when heated bythe resistance 19 to open the switch. I, however, -do-not limit myself to the use of these particular types of-relays and switches, as others suitable for-the purpose may be employed.

lathe-operation of. the-lamp circuit shown in Fig. i

when current is applied to the line itflows through the- 16 opens its contacts 17, 17'enough current is passed by i the lamp to sufficiently energize the relay coil 10, the contacts 15, 15' will be-opened and break the preheating circuit and the lamp will fire-and operate normally with current flowing through the reactance, the relay coil and ballast lamp to thepositive filament of the lamp.

In this starting operation the switch 14 only will open, while switch 16- remains-closed, as shown in full lines in Fig. 3, and coil 10 will hold the switch 14 open as long as the lamp is in operation, but if thelamp is turned off coil 10 will be deenergized and switch 14 will immediately close, so that both switches 14 and 16 will be set for a restarting action. If, however, the relay coil does not pick up and open the relay contacts 15, 15, current will continue to flow through the main preheating circuit above described until the thermostatic switch heats up sufficiently to break its contacts 17, 17 as shown in dotted lines in Fig. 3, whereupon the preheating circuit will be broken and an inductive kick will be given due to the breaking of the circuit through the reactance to fire the lamp. As the switch 16 is normally closed and is rapidly to commence restarting the lamp and this may fire, upon the application of line voltage and the preheating circuit," before the thermostatic switch has time to open its contacts, in which case relay contacts 15, 15' open the preheating circuit. This arrangement saves time in restarting a lamp which has been accidentally or inadvertently turned off. While the lamp. is operating and coil holds the relay contacts 15, open, no current can pass through the heating coil ,19 or -,fcontacts.17, 175 of. the thermostatic switch, allowing the switch-to cool in readiness for another operation,

The circuit organization shown in Fig. 4 is essentially the same as that shownrin Fig. -1 excep.t.thatthe-ballast lamp 9' is placed between the reactancer and the joined portions of conductors 4 and 11" and resistance 18 is dispensed with. This circuit permits easy substitution of the combination relay and thermal switch starter for the present FS44 starter with but little rewiring of existing, fixtures. The lamp, however, will not fire on the ap-Q plication of line voltage alone, asit is practicallyshorbf;

circuited until the thermostaticswitch 'opens and causes the reactance to give an inductive kick to start the lamp.,.

The circuit organizationshown in Figs. 5 and 6 com: prises the operating conductors fta and 5 a-leading frorn the positive and negative line terminals to the electrodes. v

As shown, the conductor la here is connected with the short circuited positive filament 3 and has reactor 8a and ballast lamp 9a arranged therein between its lineterminal point and the starter, while conductor 5a, which has the relay coil 10a arranged therein, is connected to the output terminal of the filament 2.

In this circuit arrangement the normally closed .pre-

heating conductor comprises branches 114, 12a leading respectively from the conductor 4a tothe starter and from the starter to the input terminal of the filament}, the branches being connected by a relay switch 14a. whose contacts 15a, 15a. are normally closed.. Arc s1 1ppress ing condenser ZOJhere is connected .across the contacts 15a, 15a" of the switch 14a. The heater element 1% for the normally closed thermal switch 22 is connected between conductors 11a and 12a. Onfthe negative side J of filament 2 are arranged the contactsZZ of the thermal starter which normally short circuit the coil ltla of the relay. The relay switch members 14a and lfia are arranged to open their contacts 15a, 15a and 17a, 17a 7 when current passes through the relay coil 10a.

Owing to the fact that the thermal switch contacts12 2f I andrelay contacts 17a, 17a shunt .the coil 1021 when starting, the relay cannot pick upwhen the line circuity, is closed, sothat preheating current flows tln oughthe. ballast lamp, contacts of relay 15a, ,1511, the heater ele v ment 19a, the cathode filament and through the contacts;,. of the thermal switch 22 andcontacts 17a, 174; of the relay back to the negative side of the, line.v vWhen the heater element has heated the thermal switch; sufficiently,

it opens its contacts 2 2,.which cuts the ,coil of thelrelayf into the circuit.

The relay then picks up and opens both sets of con-Q tacts, 15a, 15a, 17a, 17a. The upper set 15a, 15a t hus 5 breaks the. circuit between ,the ballast lampand filament A to cause the lamp to fire, while the lower set 17a, 17a? breaks the circuit through the normally closedtltlermal" switch contacts 22 so that whenthe heater element cools off and the thermal switch 22 recloses, saidswitchcon I opened by its snap action its time period of operation is tacts cannot short circuit "the relay coil as long as they. reduced as compared with a normally open switch which i must close and then reopen in a starting action, such as a will remain closed ready for another start when necesglow switch type of starter. As whenthe lamp fires, sary, which can commence at once .if the line circuit- 1 the relay coil keeps the relay contacts .15, 15' open'and is opened and then immediately closed again. to efiect f. keeps Current 03 the heating .c iiof the lh rm stati a substantially instantaneous. restarting of thellampf i Switch, the l r is. ay in a position t function in In the circuit organization". shown in Figs. 7 and. s case the line circuit is opened and closed again. th onstrugfion i n al i (h f a 'th'at shown Hence if the lamp is in operation and the line switch Figs. 5 and 6 with the exception thatthenegative operis opened to stop the lamp and then closed,.with,the. ating conductor is divided ,into two-branches 51 5 thermostatic switch in normal position, .all parts are ready connected at their distal ends respectively with the; nega lamp is operating. Consequently the thermal switchj agerness I tive--line'terminal and swith -the eutputezid' of tlitca'thbde -fila1 nent ,-the proximal ends of -said branchesbe'ing ar- -ranged to #formswitch circuit branches' or'ficonn'ections connection 25 connectedat-o'ne -end to the branch 50 ---through the relay coil -10b. I

The heating-resistance ?-l9b,sis here arranged in the-connecticn- 23-and-normallyopem --thermal'-'-switch=22 is a connected between thereonductorsi5e-and -25. -The rc-"' --1ay -h'ere-- comprises witch members -14b' and 16b.

Switch-member 16b is -connected:;toconductor "12a ='and provided with acontact =l7b normally engaging a contact-17b on conductor .422, whi-le switch l tb 'hasa-contact end 15b' normall y engaging. aecontact lsb onconnection 23 to close this portionofzthe prehcating'circuit,

and is movable therefrom when attracted by the coil =14b-engages -cOntact ISb whentheswitch 14b moves into engageinent withcoritact 1511 the heating resistance will be cut out ofcircuit with the conductors-w5b;--Smanddhetelaywoil lob-cut 1 into circuit therewith. Thus:the relay--switch-14b-mas normally closed contactsand normally-- --open contacts and is movable to' brea-k a:normally closed preheating circuit throughcontacts 17b, l7b'--an'dclose "a normally open or -incomplete= operatingcircuit. The relay coil is energized in parallel with=-the -heating-coil*-19bthe thermal switchdue tothe-closure of -the normallycpen contacts 22 of thethermal switch andf whefn 0nce-ener 1 gized, holds itself-- closedthrough-the contacts- 155, 15b and removes the heater-coil 19b -from-the circuit.

of thethermostatie switch I With this arrangement -the preheating-= circuit is broken I by the relay'contacts 17b; l7b'-when-the contacts of the thermosatic switch closeatten a predetermined time to permitpropen-heating' of -thecathode- -filanient.

- The arrangement shown in effect-puts the heater element in the negative lead during starting and,;once the--lamp has fired, takes the heater element out of the circuit and" puts the relayc'oil iii thei'ngative lead.

To more particularlysetjortlnthe operation of the circuit arrangement shown inFigs. 7 and 8, preheating "current in starting flows through he reactor'fiballast lamp", the relay switchwontacts 17b L 'electrode relay'switchcontacts 15b, 15b aridftlife heater element of the-thermostaticswitcli"to the inegat'ivewide of the line: A- circuit is-also"es'tablished fronithe low side of the ballast lamp to the positive filament of the lamp to facilitate the starting action. When the preheating current has heated the thermostatic switch sufiiciently, the switch closes its contacts 22', thus energizing the relay coil by placing the coil in parallel with the heater element, which causes the relay to disengage its contacts 15b, 15b and engage its contacts 15b, 15b, whereby both sets of contacts are moved fromthe position shown in Fig. 7 to the position shown in Fig. 8.

Thus the upper set of relay contacts will break the preheating circuit to the cathode filament and cause the reactor to give an inductive kick to start the lamp, while the lower set of contacts will complete the operating circuit through the relay coil and establish a holding circuit keeping the thermostatic switch heater 19b deenergized while the lamp is operating. When the thermostatic switch cools contacts 22' reopen and are ready for another start.

In the arrangements shown in Figs. 1 to 4, inclusive, and 9 to 14, inclusive, two switches are employed, one of which is thermostatically operated and the other electromagnetically operated to control the flow of preheating 17b? the cathode L'f' 6 Wand operating-currents. Ehese 'switchesmtepfefctably so constructed *and arrangedthatethey'may bec'compactly combined and enclosed inza plug-ih cali :ois casingifitindicated by dotted=lines of conve'ntiohattype In practice 5: the circuitarrangements of Figsr-l and t may be employed with very little' rewiringfrom =a=- -circuittarrangement de e-iz'si'gnedto-use a conventional starter, while'the armnge men't OfJ- igs. :5 and -7 may be-userbwithouttnpy rewiring.

Both the arrangements shown intF-igs; 5 and fl are-rel0; versible in the same sockets employeds for-ian FS-44 starter and haves-thwsameafidvantagei:ofs'Figs. -Land 4 of using full lamp currentkto energize the relay cdil' to hold the relay switch in -lampmperatin'g position onee =:"th 1am :-has*fired. I f

15 his to be-unders'tood thatzin the circuittorganiiations -----shownin'1=igs. 1; 4, 5 -and=7: the' positivei-fiiament may be short-circuited or: 1eft. 'open'-circuited,=idepehding upoh the characteristics of thewpartieulam lamb to} i'n the circuits. I

1 into thecoihform'and is fixed at its-lbwercnd tothe coil H formand hes itsmpper end terminatin'g adjacent to thc EM-top of the' form and":supported-"therein-:-by;an insulating 'block h fixed to'the' form: -'Arranged-alongs'ide 'the coil is the switch'member lt carrying" at itsrupper end'ithe :contact 15 and having at its l'ower end; a terminal 4''? suitably fixed to 'the'coi l forrn and' insulated at=such pointrfrornthe .gg 'core Terminal i ofi'the switch is connectediby the lead 11 to the prong C on the starter casing head Bt 'Exr11 =tending upward through the form is -n conductor-. having lower terminal]? andamangularly lient upper partproided with'a "U -"bend fi and a dependingfree ends-the latter r carrying the fixedbontact terminab lsr-for coactionawith s cont-act 15 of switch l4. 'r- ':-'l

@"An iadjusting screw or'b'olt q zen'g'aging the ibend .1 provides for adjustment Of contact-lSf relative toscontactlS. E, Contact=15'= is connecteii athrough:conductor k -terminal 5 j, and the input branch of conductor 13 with a terminal 13a connected at one end with the heater coil 19, which is connected at its opposite end to a terminal 13b connected in turn to a member ,k carrying the fixed contact 17' coacting with the contact 17 of the thermostatic switch (it) 16. The parts 13, 19, 13b, k and 16 are mounted on an insulated disk L supported from the head B by a terminal m conductively connecting the switch member 16 with the prong F. The disk L is formed with a hollow boss n which houses the concaved disk 16', the resistance 19 and the (i5 stem connecting said disk 16' with the switch member 16 and whereby said switch member can move to open position to break the preheating circuit therethrough when the disk 16' is heated.

Switch member 16 is so constructed that it tends to 70 move to the open position of contacts 17, 17' but is prevented from doing so by the stem connected to said disk 16', until disk 16' is sufiiciently heated to reverse its curvature. Condenser 20, as shown, is connected to prongs C and F and hence across conductors 11 and 12. 76 The arrangement of parts 14, 15, 15' is reverse to that shown in Figs. 1 and 4, but said parts operate inthe 7 same way. The operation of this unitary starter will be ireadilyunderstood by reference to the description of the operation of the circuit arrangement shown in Figs. 1,

2, 3 and 4. This starter, as stated, will operate in conneca. tionwith the'circui't arrangement shownin Figs. 1 and 4 without changes and may be adapted to operate with the other. circuit arrangements by slight changes in wiring or construction of parts.

It is to be understood that while, for convenience in :use, both switches and theirconnections are preferably placed in a starter. can, which gives practical advantages, theseparts, withinthe scope of my invention, may be placed partly within and partly without the can.- It is also tobevunderstood that while the circuit organizations are shown for example as being designed for use in connection with D, Crlampsptheymaywith little or no changes or 1suitablechanges beused in'connection with A. C. lamps.

It will also be understood that other changes may be made without departing from the invention, the scope of which is SBtfOIth in the appended claims.

Having thus described my invention, I claim: ,l. Asystem for supplying preheating and operating current to a discharge device comprising the combination of a supply circuit, a gaseous electric discharge device having two electrodes, at least one of which is constructed to receive preheating current, a relay. having an operating winding and normally closed contacts, means including an inductive reactance device and said winding ,for connecting said electrodes with said supply circuit so that said winding is'energized by the operating current of the discharge device after the device fires, a thermally operated switch having a heater and normally closed contacts, and a preheating circuit capable of producing firing temperatureelectrode heating, said circuit including in series connection said relay contacts and said thermal switch contacts and heater and the electrode to be preheated, said preheating circuit being connected across vthe discharge device and said winding in series connection so that the opening of said thermal switch causes said discharge device to. fire by an inductive voltage kick and so that'the opening of said relay contacts by'the resulting establishment of the operating current through the discharge device prevents the re-establishment of the preheating circuit when said-thermal switch cools and recloses.

- 2. A system for supplying preheating and operating current-to a discharge device comprising the combination of a supply circuit, 'a gaseous electric discharge device having two electrodes, at least one of which is constructed to receive preheating current, a relay having an operating winding and normally closed contacts, means including an inductive reactance device, a ballast and said winding for connecting said'electrodes with said supply circuit so that -saidwinding is energized by the operating current of the: :discharge device after the device fires, a thermally oper- Y ated switch having a heater and normally closed'contacts, and-a preheating circuit capable 'of producingfiring tem-- perature electrode'heating, said circuit including in series:

connection 'said relay contacts and said thermal switch contacts and heater and a current limiting resistance and 'the electrode-to be preheated,-=saidpreheating circuit be-- ing connectedacross said'discharge device and said ballast andsaid winding in series'connection'so that the opening of said thermal switch=causes the discharge device to fire- .by an inductive'yoltage'kick and so that the opening of 1 said relay contactsbythe' resulting establishment of the operating current through the'discharge device prevents the re-establishment' of the preheating circuit when said thermal'switch cools and reclose's. Y

3. A system for supplying preheating and operating current to a dis'charge'device comprising the combination o f -a supply circuit, a gaseou'selectric discharge device having two electrodes, one of which is constructed to receive pre-heati ng current, a relay having an operating winding and normally closed contacts, means including an inductive reactance device, a ballast and said winding for connecting the other electrode of said device with said supply circuit so that said winding is energized by theopcrating current 'of-the discharge device after the device fires, a thermally-operated switch having a'heater and normallyclosed contacts, and a preheating circuit capable of producing firing temperature electrode heating, said circuit including in series connection said relay contacts and said therm'al switch contacts and heater, one end of 1 said'circuit being; connected to said ballast and the other "end ofsaid circuit being connected to one end of the electrode to be preheated, the opposite-end thereof being connected tothe opposite side' of said supply circuit, said "seriesconnected relay and switch contacts being thereby connected across said electrodes and said winding in series connection so that the opening of said thermal switch causes the-discharge device to fire by an inductive voltage kick-and so that the openingiofsaid relay contacts by the "resulting establishment "of the operating current 1 through the discharge device prevents the re-establishment ofthe preheating circuit when said thermal switch cools recloses.

Babb July 27, 1948 

